Field of the Invention
The invention relates to technology of an electronic cigarette and more particularly relates to a power control circuit and a power control method for the electronic cigarette.
Description of Related Art
FIG. 1 is a circuit diagram of a conventional electronic cigarette. Please refer to FIG. 1. An electronic cigarette 10 includes an integrated circuit 110, a microcontroller MCU, an inductor L, and a heating wire 120. The integrated circuit 110 has pins LC1, LC2, VIN, EN, PGND, VOUT, and FB. The microcontroller MCU is coupled between the pin VOUT and the pin FB. The heating wire 120 is coupled between the pin VOUT and the pin GND. In the electronic cigarette 10, a load current that flows out of the pin VOUT is fixed. The microcontroller MCU is for controlling a feedback signal of the integrated circuit 110, so as to control an output voltage at the pin VOUT, thereby controlling the power of the electronic cigarette. Because the microcontroller MCU has the responsibility to control the output voltage, the electronic cigarette 10 usually requires other sensing circuits (not shown) to assist the microcontroller MCU in generating a pulse width modulation control signal 130.
FIG. 2 is a circuit diagram of another conventional electronic cigarette. Please refer to FIG. 2. An electronic cigarette 20 includes a pulse width modulation control circuit 210, switches 211-214, a heating wire 220, a capacitor 222, comparators 224-225, and a microcontroller MCU. The electronic cigarette adopts a buck-boost configuration. The microcontroller MCU controls a feedback path from an output voltage VOUT1 to the pulse width modulation control circuit 210, wherein a feedback circuit includes the comparators 224-225. The electronic cigarette 20 uses the microcontroller MCU to output a signal and transmits the signal to the pulse width modulation control circuit 210 via the comparators 224 and 225, so as to adjust the output voltage VOUT1.
The conventional electronic cigarettes 10 and 20 both use the microcontroller MCU, and the load current outputted by either of them is fixed, and they both control the output voltage to control the power. While the microcontroller MCU is used, usually other complicated circuits are required for performing detection. Therefore, the microcontroller MCU and the complicated circuits occupy a relatively large area with respect to the area of the entire circuit.